When kayaking on a river, lake or ocean, many kayakers propel themselves with a double-bladed paddle. Due to the rotation of one's torso combined with raised hands during a forward stroke it is necessary to feather the kayak paddle. In addition kayakers often encounter windy conditions when kayaking—especially on a large lake or an ocean, a kayaker's paddle is often feathered to reduce the wind drag of the paddle blade not in the water. Feather is the angular relationship of the plane of one paddle blade relative to the plane of the other paddle blade and is often expressed as the angle between the planes. Feathering a paddle alleviates potential stress on the wrists, which may be significant over a long excursion. Because kayakers use a variety of paddling styles, a paddle whose feather may be adjusted allows a kayaker to modify his/her paddle to match his/her style and conditions.
There are many conventional coupling arrangements available that allow one to adjust the feather of a paddle. An example of a conventional coupling arrangement is shown in FIG. 1 and includes a collet 10 to frictionally couple shaft sections of a paddle with each other. As shown in FIG. 1, the collet 10 includes a collar 12 mounted to a shaft 14, and a compression nut 16 that slides along the shaft 18. When the collar 12 is engaged with the compression nut 16, the shaft 18 is frictionally prevented from moving relative to the shaft 14 due to constriction of the collar 12 around the shaft 18.
Unfortunately, the collet 10 has some problems. One of the problems is that the collet 10 frequently does not securely couple the shafts 14 and 18 with each other. Because the collet 10 frictionally couples the shaft 18 with the shaft 14, twisting and/or pulling the shaft 14 relative to the shaft 18 can cause a loss of desired feather in the paddle and can cause the shafts to separate. To more securely couple the shafts 14 and 18 with each other, one may increase the constricting force on the collar 12 by threading the compression nut 16 further along the collar 12 with much force. But this induces undesired stress in the collet 10 and the shaft 18, which typically causes the collet 10 to wear out prematurely. Furthermore, the compression nut 16 may become stuck with the collar 12 and make uncoupling the shafts 14 and 18 to adjust the feather of a paddle difficult.
Another example of a conventional coupling arrangement is a button (not shown) that protrudes from a first shaft of one paddle section into a hole (not shown) in a second shaft of another paddle section. To provide different indexed positions, and thus different feather angles, more than one hole is located about the circumference in the second shaft. The button typically travels in a radial direction or perpendicular to the longitudinal axis of each shaft and is biased away from each shaft's longitudinal axis by a spring; the hole is typically sized to closely receive the button. Once inserted into the hole, the button prevents the shafts from rotating relative to each other and may further prevent the paddle sections from being pulled apart as one uses the paddle.
Unfortunately, this type of coupling arrangement also has some problems. The number of different indexed positions is limited to the number of holes the shaft can include without causing the shaft to buckle or permanently deform under the strain of use. In addition, the holes in the shaft or the button often deform from the force imposed by the respective button, or shaft over prolonged use. This causes the feather of the paddle associated with a specific indexed position to change over time and introduces play or undesirable movement between the paddle sections when the sections are connected to each other. This undesirable play in turn hastens further deformation of the hole and the eventual permanent deformation or failure of the paddle.